1. Field of the Invention
This invention relates generally to trowels for use in spreading of a cement or adhesive on a substrate surface for the laying of tiles on the substrate surface, and more particularly relates to a notch trowel having a substantially rigid trowel blade portion with a peripheral blade edge having a notch pattern providing improved contact between the cement or adhesive and applied tiles, a wedge member or shank for prying up tiles to be removed, and an ergonomic reversible grip handle used to manually grasp the notch trowel.
2. General Background and State of the Art
Trowels are commonly used for spreading cement or adhesive for installation of tiles on a substrate surface such as a wall or floor. Such trowels typically have a generally flat blade portion for spreading and smoothing the cement or adhesive, and a handle connected to the blade portion. Such trowels are also commonly used to pry up tiles to be removed, which can bend and otherwise damage the trowel to such an extent that the trowel can become unusable for spreading cement.
One conventional trowel is known having a blade that includes two adjoining edges having multiple notches, for spreading cementitious material, and a third edge that includes a rectangular extension of the blade for use as a margin trowel for prying up tiles. The trowel also includes a tubular handle rigidly attached to the trowel body.
Conventional notch trowels have used patterns of notches having square, rounded, saber tooth, and triangular shapes, as well as rounded shapes with obliquely angled sides flaring outwardly and inwardly. One conventional adhesive trowel has a blade edge with large notches, and small notches interspaced between the large notches. It has been found that spreading of cement or adhesive with a trowel having square notches or round notches commonly forms air bubbles in the cement or adhesive, interfering with optimal contact of the cement or adhesive with applied tiles, requiring application of heavy pressures to improve the degree of contact to an acceptable amount. For example, without application of pressure to applied tiles, such notch trowels commonly provide a contact spread with the tiles of only about 50%, indicating that approximately half of the surface of the applied tiles faces a space left between ridges of the cement or adhesive. In order to achieve a greater contact spread of 80%, which is considered to be the industry standard, it is commonly necessary to apply heavy pressures to tile applied to a cement or adhesive spread on a substrate surface, which can cause the contact spread to be inconsistent. It would be desirable to provide a notch pattern that can achieve a greater contact spread of 80%, without the application of heavy pressures, and with improved consistency.
It is also often necessary to turn a trowel around to use the trowel backwards to use a smooth flat side of a trowel to fill in pores or spaces in spreading cement based adhesive. This can be accomplished by switching from using the dominant hand to the non-dominant hand in using the trowel, i.e. using the trowel with both the left and right hands for the different directions of use of the trowel, but this can be awkward for users who are not ambidextrous. For trowels with a conventional short cylindrical configuration with a relatively thin rod connecting the handle to the blade portion of a trowel, using the trowel forwards and backwards with the same hand can be awkward. Although trowels having a handle with a “D” shaped configuration allow the trowel to be more easily reversible for use with a dominant hand, this type of handle is commonly centered on the blade of the trowel, making use of the trowel equally awkward forwards and backwards, with either hand.
It would be desirable to provide a notch trowel with a wedge on one side of the trowel allowing a user to use the wedge side of the trowel as a margin trowel to pry up tiles. It would also be desirable to provide a notch trowel with a notch pattern with conically shaped trapezoidal and parabolic notches with non-parallel sides to produce improved suction of the notches over the cement or adhesive to be spread, and that provides an improved, more consistent contact spread of cement or adhesive. It would also be desirable to provide a notch trowel with an ergonomic reversible handle with a rounded shoulder and thinner neck portion, allowing users to more easily turn the trowel around to use the trowel backwards with a dominant hand. The present invention satisfies these and other needs.